Rune gauntlets are a reward that can be purchased with tokens from the Fist of Guthixminigame. They come in "charged form" and do not degrade during use, unlike the other Fist of Guthix rewards.

The gauntlets will only lose their charge if you right click and use it on Reggie (Fist of Guthix NPC) or if you die and you pick them up from your gravestone. They will not lose charge if they are one of the items protected on death or if you are playing safe fighting activities like Fist of Guthix or Clan Wars. Also you can talk to Reggie and have him recharge them for 35 tokens. They can only be traded in uncharged form and require 50 Defence to wear.
Uncharged (worn-out) Rune gauntlets have no bonus. Currently they provide 1151 coins per FoG token.